http://www.thehorse.com/videos/30371/how-to-read-a-horses-lip-tattoo
Saturday, 21 February 2015
Choose Tendon Injury Cases Carefully for Stem Cell Success
With any new veterinary treatment approach there come research studies, experiences, and opinions about what works best and why. Stem cell therapy is no exception. One veterinarian recently reported that at least for tendon injuries, the cases practitioners choose to target with stem cells and how they prepare those cells have more bearing on treatment success than the stem cell source they select.
Roger KW Smith, VetMB, PhD, DEO, FHEA, DECVS, MRCVS, professor of Equine Orthopaedics at the Royal Veterinary College, in Hatfield, U.K., shared this and more about what he and his colleagues have learned about stem cell treatment at the 2014 American Association of Equine Practitioners Convention, held Dec. 6-10 in Salt Lake City, Utah.
Mesenchymal stem cells (MSCs) can come from a variety of sources, though practitioners most often use bone marrow or fat (also termed adipose-derived stem cells). Umbilical cord cells and fetal tendon cells have come on the scene more recently, he added.
Cells can come from the horse that’s being treated (autologous therapy) or from a bank (allogeneic), though veterinarians in the U.K. are restricted to autologous because the U.K. does not currently allow allogeneic stem use, as the United States does.
But he does choose his cases. “The only requirement, really, for this particular treatment is a contained defect in a tendon or ligament,” he said. In other words, he and colleagues ideally want to treat a structure with a “central cavity surrounded by intact tendon tissue that can act as a receptacle” for the stem cells. The superficial digital flexor tendon (SDFT) is ideal because injuries to this structure generally meet this description and “because it’s the most common and for which we had comparative outcome for other treatments.” There is no minimal requirement for lesion size but veterinarians don’t generally inject smaller lesions because they have a better prognosis and are more difficult to inject. Stem cells are often focused on the most severe injuries.
Smith avoids treating traumatic injuries--those associated with external trauma to the leg, such as a cut or blunt trauma, rather than an overstrain injury due to overloading of the limb with prior tendon degeneration--with stem cells because studies have shown that open defects in tendons do not retain any implanted stem cells. However, if he feels there is enough time for a granulation tissue bed to form in the defect, then treatment is possible and can be effective. Timing is important; generally, the earlier he treats the injury with stem cells, the better the outcome.
Access to allogeneic stem cells would mean that, yes, he could implant them earlier. But the lag time before first treatment with autologous cases (about three weeks, due to the time it takes to aspirate bone marrow and expand the cells in the lab) isn’t all bad news because it gives the body a chance to establish a vascular supply to support cells after implantation. This usually happens within one or two weeks after injury.
As for selecting MSC cell type, again, he focuses on preparation rather than source. Smith classifies MSCs as either minimally manipulated stem cells (which is often the case with fat-derived) or enriched stem cell products (when MSC populations are expanded by culture in the laboratory). Then he looks at what the case requires. “Culture and expansion is necessary if it is deemed important to produce an abundant and homogenous stem cell preparation because of the low numbers of MSCs in the source material,” he noted, mentioning that only one in 100,000 of the nucleated cells (cells that have a nucleus—in blood these are usually white blood cells, as red blood cells have no nucleus) in bone marrow is an MSC, hence the need for culture/expansion.
Smith uses cultured bone-marrow-derived MSCs in his practice and reported that he has increased his standard dose to 20 million cells (at a concentration of 10 million cells/mL) with the option to increase this twofold for larger lesions, “because of the large loss of cells post-implantation and clinical outcome analysis has indicated better outcome with this large number.”
Smith summarized the techniques he uses to aspirate (both from the sternum and the tuber coxae--the bony prominence of the hip behind the flank) and administer bone-marrow-derived stem cells to treat tendon injuries. Some of the tips he included were to:
- Be sure the entire needle is visible on ultrasound to avoid inadvertent perforation of the deep surface of the tendon where cells would leak out.
- Inject stem cells into one to five sites, depending on the nature of the core lesion. An injury further along in healing will require more injection sites because the cells cannot spread as well through echogenic (more filled in) tissue.
- After administering MSCs, apply stable bandages to maintain the limb's temperature to maximize healing. “This is more important in cold climates, as distal limb temperature is then several degrees below core temperature and most cells are happiest at 37 degrees C (98.6 degrees F),” said Smith.
As is the practice at this peer-reviewed meeting, Smith disclosed that he was formerly a director and technical advisor of VetCell Bioscience Ltd and is currently a scientific advisor for Recellerate Inc.
About the Author
Stephanie L. Church, Editor-in-Chief
Stephanie L. Church, Editor-in-Chief for The Horse, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, VA. Her background is in eventing, and she enjoys photography, cooking, cycling, swimming, riding her friends’ and family’s horses, and traveling in her free time.Mending Tendon and Joint Injuries with PRP
Photo: Thinkstock
What makes recommendations for regenerative therapies such as platelet-rich
plasma (PRP) inexact is that these approaches are based in biology, not
chemistry, said Lisa A. Fortier, DVM, PhD, Dipl. ACVS, of Cornell. Each
preparation is just as variable and unique as one horse is to the next.
Recognizing this can go a long way in setting clients’ expectations for
treatment success using these therapies and also in understanding the
controversy that surrounds the best ways to use them. All veterinarians can do
for the moment is choose cases carefully, extrapolate from current evidence
when formulating treatment plans, and be sure to use traditional rehabilitation
techniques as well.“These are not drugs, they are not perfect, and they are not going to work when all of your other approaches fail,” said Fortier, who is professor of large animal surgery at the university’s vet school, in Ithaca, New York. She summarized current research on PRP and what she’s learned using it at the 2014 American Association of Equine Practitioners Convention, held Dec. 6-10 in Salt Lake City, Utah.
The “tremendous degree of variability” among PRP preparations has to do with platelet and leukocyte (a type of specialized white blood cell that aids in healing) concentrations. Current evidence suggests that PRP preparations with platelet concentrations two- to fourfold over what's found in blood and low numbers of leukocytes are optimal for increased tissue repair.
Veterinarians initially used PRP for treating tendons and ligament injuries, but Fortier said there is now evidence it can help heal joint injuries as well. Research has shown that PRP can increase synovial cells’ synthesis of hyaluronic acid (HA, an important cartilage component that helps maintain hydrostatic pressures to resist weight-bearing forces) and decrease joint pain and inflammation, making it a promising approach for enhancing early return to activity. Therefore, she recommended only using it in mild to moderate joint disease and pointed to human research: “PRP didn’t do anything to help regrow cartilage in human knees, but it did help with pain and returning people to functional activity.”
Additionally, long-term, PRP was as—or more—effective than HA in restoring function and decreasing pain in human knee arthritis cases, but the effect lasted longer (a year or more vs. six months for HA).
She said PRP injections can increase tendon matrix production and decrease inflammatory mediators associated with matrix degradation. As with other therapies, however, one of the keys with PRP treatment is treating an injury early—injecting it into a lesion within a few days of injury can stop the progression and growth of a lesion and avoid scar tissue formation.
Fortier reviewed a few questions she commonly fields about PRP:
- What’s the time frame for successful intervention? It depends on the site and injury severity, but is likely limited to three- to six-month-old injuries.
- Do I need to add thrombin (an enzyme involved in blood clotting) to activate PRP before injecting it? No, she says. “When you put PRP into tissue, it clots naturally.”
- After preparing it, how do I know if I actually have PRP? “Make a smear of whole blood and the PRP, let them air dry, come back and count platelets and stem cells; there should be more in your PRP smear compared to the blood smear,” she suggested. “Some (horses) are going to be super PRP makers, and others are not.”
- How long can PRP sit out at room temperature? “It’s safe to draw the blood, do a couple of more farm calls, and then go back and inject the PRP,” she said. “You can store it for about a year in the freezer without problems.”
- What size needle should I use, and how much PRP should I inject? Fortier uses a 23-gauge needle to minimize damage to tissues. For lesions, she simply fills them up with PRP. For joints, Fortier injects 1-3 mL for smaller joints and 3-5 mL for larger ones. But it is important to point out that if injecting stem cells, you need a larger needle—nothing smaller than 21-gauge to avoid killing the stem cells.
- What’s the horse’s level of activity following treatment? The horse resumes active rest with a graded rehabilitation program aimed at getting the horse back to full work in four to six weeks for a joint injury and three to six months for a tendon injury. An attractive aspect to this treatment, she said, is that the horse can go back to work relatively quickly.
She also said to remember that even PRP applied early will not cure the horse without other rehabilitation techniques, which include controlled exercise, weight loss, and consistent and good shoeing.
Fortier acknowledged it is unclear which biologic approach is best for certain injuries, given the variable nature of biologic therapy, but veterinarians are commonly using a dual PRP/stem cell approach to counteract the time and performance lost with musculoskeletal injuries.
As is practice at this peer-reviewed meeting, Fortier disclosed she is a consultant to Arthrex Inc.
About the Author
Stephanie L. Church, Editor-in-Chief
Shipping Horses Long Distances
Photo: iStock
I’ve recently begun searching
for a new horse to welcome into my life, and I find myself looking at animals
farther and farther away from of my home state of Texas. The process has
reminded me how important climate and other considerations can be when shipping
horses long distances. The following are some factors to consider when
transporting horses afar, be it to a show or to a new home.
If you’re planning to ship a horse for more than
three to four hours, think about his health first. Practice proper preventive
care, vaccination, and deworming prior to travel. If your horse isn’t a
frequent shipper, you might need to update his vaccines and have your
veterinarian perform an overall health check at least two weeks before hitting
the road. Your vet might also recommend doing blood work to determine if your
horse is healthy enough to undertake long-distance travel or getting an updated
Coggins test if your horse’s is more than 6 months old. Some states require
proof of a current negative Coggins pulled within the prior 6 months for travel
across their borders.
If your horse requires vaccination, schedule it
early enough that the horse’s immune system gets a boost before the stress of
shipping—which provides its own set of challenges to even a healthy immune
system—and any disease exposures off the farm. This is also a good time to talk
to your veterinarian about health certificate requirements and any concerns he
or she might have about your horse’s destination, as animal health regulations
can vary from state to state and often change depending on disease
outbreaks.
Keep an organized folder of vital paperwork such as
vaccine history, Coggins test results, health certificates, and registration
papers while traveling. Talk to your veterinarian about preparing a first-aid
kit to keep on your trailer in case of emergency. If you already have one, make
sure all medications contained in it are labeled and have not expired.
If hauling your own horse rather than hiring a
shipping company, it is important to make sure your truck and trailer are ready
for long-distance travel. Check your tires and lights to ensure all are in good
working order. Give yourself time to repair any potential issues so you are not
in a last-minute rush. This is also a good time to clean out the trailer and
pack it with necessities such as enough water for your horse to consume during
the trip. Water in different parts of the country can taste significantly
different, and some horses are very picky about the water they drink. The last
thing you want to deal with on a long road trip is a horse that suffers an
impaction colic because he does not want to drink water along the way. I also
recommend taking enough hay to cover your travel needs plus at least a couple
of days. Just as with water, hay and hay quality can vary greatly throughout
the United States and other countries.
If possible, do not restrict your horse’s head or
neck position during long trips (six or more hours) because researchers have
linked upward head restraint with compromised lung clearance and an increased
risk of shipping fever. Also remember that ventilation is vital to healthy
travel, and horses locked in a trailer with no air flow can become very hot,
especially during summer. On long trips schedule rest stops for your horses
and, if possible, time for them to unload and drink water. Offer your horses
good-quality hay and water at least every four to six hours during travel
(every three to four hours in summer). If you are able to unload horses during
stops, this is also a good time to remove any manure and urine-soaked bedding
from the trailer so horses are not breathing ammonia-filled air any longer than
necessary. Another good idea for long-distance travel is to plan overnight
stopping points along the way. Many farms are willing to rent space to owners
traveling with horses. Scout these facilities out ahead of time, and have a
backup plan in case there is a problem with your first choice.
After arriving at your destination, allow your horse
sufficient recovery time before asking him to work or perform. For travel times
under 12 hours, 24 hours of rest is typically adequate for recovery. Horses
shipping for longer than 12 hours or by plane often require at least two to
three days of rest and recovery. During this period watch your horse for any
signs of illness, such as nasal discharge or coughing, inappetence or poor
water consumption, and abnormal manure production. Call your veterinarian
should you note any of these problems, as they can indicate shipping fever or colic
post-travel.
With proper preparation and planning, you and your
horse can have an easy and enjoyable long-distance trip.
About the Author
Kristen Slater, DVM
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